Commercially available quality control materials are routinely used in the clinical diagnostics laboratories to monitor the precision and accuracy of both manual and automated clinical test methods and procedures. Development of multi-analyte and multi-level quality control materials, however, is very complex due to differences in chemical and physical properties of the biomarkers/analytes in the control (molecular weight, solubility, reactivity, stability, interferences from other analytes, etc).
Multi-analyte and multi-level quality control materials typically have stability and performance limitations for at least one analyte because conditions which may improve stability of one analyte may be detrimental to stability of another. For example, Randox Liquid Chemistry Premium Plus has a performance limitation for stability of total and direct bilirubin, and the instruction pamphlet states that total and direct bilirubin values gradually decrease during the product shelf life. In addition, the instructions for MAS® ChemTRAK® Liquid Unassayed Chemistry Control (Thermo Scientific) states that bilirubin may decrease over the product shelf life and phosphorus, salicylate, and triglycerides may increase over product shelf life.
Available urine chemistry quality controls can suffer from the poor stability of creatinine. This biomarker is a clinically important analyte in commercially available urine chemistry controls because it is used to evaluate the renal function. An example of a urine chemistry quality control with poor stability for creatinine is MAS® UrichemTRAK® (Thermo Scientific). The instruction for use for this quality control states that creatinine values may decrease over the product shelf life.